1. Field of the Invention
The present invention relates to a method for securely managing information in a database, and more particularly, to a method for storing and securely managing important information for a user in a database.
2. Description of the Related Art
FIG. 1 is a diagram of a related art communication system, for example, an Internet system, for Digital Rights Management (DRM). User computers 10a . . . 10d, a content providing server 141, a key-data management server 142, and a payment system 143 are connected to one another through a communication network 12. The content providing server 141 provides content to the user computers 10a . . . 10d and receives charges related to DRM through the payment system 143. The key-data management server 142 manages key-data for encrypting and decrypting content files, which the content providing server 141 provides to the user computers 10a . . . 10d. 
Referring to FIG. 2, a related art content file includes a header 31 and data 32. The header 31 includes encryption information EI, user key-data KU, and DRM information DRM. The encryption information EI contains parameters used for encrypting the data 32, and the user key-data KU is used for encrypting and decrypting the data 32 of the content file. The DRM information indicates the number of use times permitted to a user.
However, the related art system and method has various problems and disadvantages. For example, but not by way of limitation, according to a simple method of managing information with such a related art file structure, the header 31 can be decrypted by a hacker even if it has been abstrusely encrypted. Accordingly, the hacker can change important information for a user such as DRM information. Therefore, in addition to encryption of information, it is necessary to efficiently determine whether the encrypted information has been accessed and/or altered without authorization (i.e., hacked) to securely manage information in a database.